Every tracked fact about the two, side by side - prices, history lows, ratings and measured tuning. No verdict: which one to buy is the visitor's decision, always.
Both sides are headphones. The rows below are the facts each store publishes for this shelf - driver setup, impedance, sensitivity, back design and connectivity. A dash means the listing does not state that spec.
SpecKossSennheiser
Driver configuration—Dynamic (DD)
Impedance—150Ω
ConnectivityWiredWired
Back design—Open-back
Measured tuning, side by side
Both curves are real community measurements (gold: Koss · blue: Sennheiser). Each is level-aligned to its own 200 Hz–1 kHz mean, so rig offsets don't skew the comparison.
KossSennheiser
Average level per band, relative to that curve's own 200 Hz–1 kHz middle - a taller bar plays louder there on the measured files. Same colours as the chart above.
Wearing your own earphones or headphones? Pick them here and the player pre-corrects for their sound, so the demo plays the target tuning itself - not both mixed together.
Same signal through both tunings at once - slide to blend. Start on pink noise for the clearest read.
Tuning distance±2.64 dB RMS84% match - Close. Computed on a shared 40-point log grid, 20 Hz–10 kHz. A measurement-space fact, not a promise two ears agree.
Bass · 20–250 HzKoss +0.2 dBAverage level difference in this band, both curves aligned to their own 200 Hz–1 kHz mean. Plus means Koss plays louder there on the measured files; minus means Sennheiser does.
Mids · 250–2,000 HzKoss +0.7 dBAverage level difference in this band, both curves aligned to their own 200 Hz–1 kHz mean. Plus means Koss plays louder there on the measured files; minus means Sennheiser does.
Treble · 2,000–10,000 HzKoss −0.9 dBAverage level difference in this band, both curves aligned to their own 200 Hz–1 kHz mean. Plus means Koss plays louder there on the measured files; minus means Sennheiser does.
What a curve cannot seeBuild, driver QC unit-to-unit, comfort, isolation, accessories, warranty and resale value sit outside the graph - usually what the pricier one is charging for.
Price over the last 30 days
Daily lowest price across every tracked store, from the site's own price history. The line is one product's own range - the two cards are not drawn to a shared scale.
Koss - KPH30i (Unboxed) - BlackNow ₹2,499at its 30-day medianLowest on record ₹2,499 on Tuesday, 27th Oct, 2026In stock at 1 tracked store
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Sennheiser HD 660 S - Dynamic Open-Back Stereo Headphone
Sennheiser
Lowest on record ₹33,718 on Sunday, 4th Oct, 2026
★★★★★ 4.8 4.8 · 470 reviews
Full prices & history